This is a signless front-mount post. Although located along the creek, it is doubtful that it ever held a "Brandywine Creek" marker, ast stream markers were typically on a top-mount post. It may once have held a now long-gone "traffic" type iron marker. Seems too far from a town boundary to have held a town-name sign.
March 2012 photo by JGl
This is a signless post that may have once held a stream name marker